1. Field of the Invention
The present invention relates to a high-frequency incision device for excising tissues in a lumen of a body by being used together with an endoscope.
2. Description of the Related Art
A high-frequency snare has been known as a device to be introduced into a lumen of a body by the use of an endoscope for excising tissues in the lumen. As disclosed, for example, in Jpn. Pat. Appln. KOKAI Publication No. 6-217985, the high-frequency snare includes a conductive wire whose leading end is bent to form an elliptical snare loop, by means of which the tissue in a lumen is bound up tightly, while high-frequency current is passed through the conductive wire, thereby excising or removing the tissue. In such a high-frequency snare, the snare loop has a length in the longitudinal direction longer than the opening width in the transverse direction and its loop surface is positioned on an extension of a center axis of the device.
High-frequency snares have been disclosed in the above Jpn. Pat. Appln. KOKAI Publication and Jpn. Pat. Appln. KOKAI Publication No. 10-85230. In such disclosed devices, in order to facilitate the operation of grasping the tissue present in a zone in front of an endoscope and the incision device, an operation for raising the snare wire is performed to bring the loop plane into a position where the loop plane is intersected by the center line of the endoscope and the incision device.
In recent years, there have been very many clinical reports relevant to lesions spreading transversely to the axial direction of the lumen and lateral spreading tumor (LST) in the field of medical treatment of large intestine.